Well, just to maybe shed a ray of light on the subject as I see it.

On the UPX website forum for "Our Happy Customers" I see 59 posts.

According to Microsoft claims, they tested over 2 Million applications for compatiblilty with Windows XP before RTM.

When writing an application using Microsoft Assembler and Visual C v6.0 one has to make many choices for compiling for the best size. This process often includes hundreds of various resources that Microsoft has worked on compatibiltiy testing already to a degree further then any other vendor in this area.

I don't think anyone is disagreeing that it is not possible, but come on, one has to be realistic as well. This is not the only compressor out there and were not talking a 5MB+ DLL like many applications have.

The author writes KiXtart on his own time and has to debug on his own time to a degree he feels comfortable with making a beta version available. By now throwing in the mix a compression routine that has issues as well. (I see 132 posts for "Troubles with decompression of packed exes")

Your scripts can also be setup so that the user doesn't even see or know it's running, so what are we really talking about here? An IDEOLOGY which may or may not be accepted by everyone.

You can easily compress your version though as you already know and run along happy. I can't speak for Ruud, but if I were in his shoes I don't think I'd care to spend the extra time and effort involved to achieve such a small gain at the expense of potential unknown bugs or other issues.

As for the newer features in the lastest KiXtart, there are hundreds of minor fixes, updates, new features and yes, as Shawn has said, a LOT of current size is due to still maintaining Windows 9x support.

If you know of a smaller/better/as-complete scripting language please let us know.
Have you checked the size of Perl/Python/VBscript ? They are MUCH larger then KiXtart and require external libraries to support anything close to what KiXtart supports in a single EXE.